Lower air grille



FIG. 1 is a front perspective view of a lower air grille showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a side view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom view thereof.

It will be understood that the broken lines shown in the drawings illustrate portions of the lower air grille that form no part of the claimed design. 

CLAIM The ornamental design for a lower air grille, as shown and described. 